－Are you sure you have to? It’s been so late. Make it another time?－I don’t know I can do

问题补充：

－Are you sure you have to? It’s been so late. Make it another time?

－I don’t know I can do it if not now.

A. how

B. what

C. when

D. that

答案：

A. how

B. what

(答案→)C. when

D. that

解析：考查宾语从句的引导词。根据句意可知这是一个宾语从句。I can do it结构很完整，所以只能用连接副词。结合句意可知C正确。句意：我不知道如果不是现在我什么时候可以做这件事情。